Scoring a seat on a subway car isn’t a game of chance — for savvy New Yorkers, it’s an art.

Where you choose to enter the train and the seated passenger you choose to stand in front of are both aspects of a silent seat-stealing science that London-based digital strategist Brendan Nelson has carefully mapped.

“I realized there were strategies going on all around me,” said Nelson, who notes that the tricks he uses in London’s “Tube” apply to the Big Apple’s subways. “The more I looked for them, the more apparent they became.”

Nelson divides straphangers into three categories: occupants, civilians and aspirants.

Aspirants want a seat and stand in front of people they hope will get up. Civilians aren’t trying for a seat at all. And occupants have already scored a seat.

Nelson’s advice to aspirants: Just play it cool.

“Seem too predatory and you’ll raise the suspicions of other aspirants, losing the element of surprise,” he writes in his diagrams. “Let them think you’re a disinterested civilian.”

Tactics include profiling passengers. A student riding the Brooklyn-bound R train, for instance, is likely to get off at NYU, while chances are a Birkenstock-sporting mom is going to sit all the way to Park Slope.

Other aspirants play mind games. They pretend to allow a rival aspirant to snag a seat but are banking on his returning the favor and offering it right back.

The most competitive aspirants use reflections in subway-car windows to keep an eye on seats behind them, Nelson says.

Others “pre-walk” the station platform so they can enter the least crowded car.

New Yorkers admit their desire for seats doesn’t always bring out their best behavior.

“I get ready like I’m in a race, at the beginning of a meet,” said Straphangers Campaign spokesman Gene Russianoff, describing his daily quest to get a seat. “I have my backpack in my hand, and I’m tensed and ready.”